Federal agents have been scouring the streets of Minneapolis in the days leading up to the Super Bowl, trying to get rid of counterfeit merchandise - a scam they say has serious ramifications most people in search of a memento, never consider.

Experts say it's a very serious crime with a lot of negative consequences.

For one, the fake stuff drains the local economy, bilking it out of millions of dollars that local workers will never see.

"All that money is going back to China and is funding black market criminal organizations that are involved in other illicit activities like drug trafficking and forced labor," said Matthew Bourke, Department of Homeland Security.

How can you be sure that what you're getting isn't doing that? First, start with the tag.

"The first thing you should look for is a UPC code that's going to be on the tag," said Bourke. "You'll never find this on the counterfeit jersey."

Most of the real stuff will also have a hologram. Some fakes are better than others, and appear to include one.

"But it's not a legitimate hologram that, if you turned it to the left or right, the picture doesn't change. It's just a silver sticker," said Bourke.

Still not sure?? Experts say turn it inside out.

Bogus items will rarely fool you on the inside. Look for loose stitching or decals that look like they would tear away. The real items just feel better and won't get ruined after one wear.

"This stitching is tied off, tied here, so that when you put it in the wash it doesn't get destroyed," said Bourke. "You can play a game of football wearing this, and I think you'll be OK."